Seaweed supplement diet for enhancing immune response in mammals and poultry

ABSTRACT

Seaweed supplement is included in diet of mammals and poultry to enhance immune response. In one embodiment, pasture forage is treated with seaweed supplement. When cattle or lambs are grazed on seaweed supplement treated endophyte-infected forage, immune function is preserved or depressed immune function is reversed. The enhanced immune function continues to the feedlot finishing phase even though no seaweed supplement is fed in that phase. In an independently inventive embodiment, seaweed supplement is administered to pigs exposed to PRRS disease to impart resistance to said disease and improve performance. In still another independently inventive embodiment, seaweed supplement is administered to lactating mares prior to weaning to mitigate the stress of weaning.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. patent application Ser. No. 09/469,176,filed Dec. 21, 1999 pending and a continuation-in-part of U.S. patentapplication Ser. No. 09/032,104, filed Feb. 27, 1998 now pending.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to seaweed and treated seaweed feed supplementsfor mammals and poultry wherein the host exhibits enhanced immuneresponse. In another aspect, the invention relates to the introductionof seaweed supplement directly to mammal and poultry feed as well asintroduction of grazing animals to plants and grasses, which have beenpre-treated with seaweed extract. In still another aspect, the inventionrelates to seaweed feed supplement, which enhances the host immunesystem for periods beyond cessation of seaweed supplement introductionto the host diet. Aspects of the invention also relate to impartingresistance to Porcine Reproductive and Respiratory Syndrome (PRRS)disease in pigs that have been exposed to PRRS disease and to mitigatingthe stress of weaning in lactating mares.

2. Description of Related Art

Seaweeds have been used through antiquity in crop production and asearly as the 1950's, evidence of plant growth hormones in seaweed wasreported. Seaweed is now recognized as a source of plant growthregulators and has been demonstrated to have activity that includescytokinin, auxin, gibberellin, and idole acetic acid. Seaweed has alsolong served as feed for domestic and wild animals. Some even graze onseaweed growing on rocky beaches and floating in the ocean water.Seaweeds have been dried and sold as a meal product to be mixed withother feed stuffs. The value of seaweed has been generally attributed tothe fact that it is low in carbohydrate and proteins and rich in traceelements; including vitamins B,D,E and vitamin precursors includingbeta-carotene; and various growth hormones.

Bacterial, fungal, viral and other disease causing agents infect mammalsincluding man, other mammals, plants, insects and poultry. Theprevention and control of, for example, diseases have important healthand economic implications. Diseases contribute to infections in humansand other mammals including common colds, herpes and cancer and theimportance of their control is obvious. Also important is control ofagent diseases in mammals and poultry for economic reasons as well asthe ability of such mammals and poultry to become disease reservoirs orcarriers, which facilitate the spreading of diseases to other hostincluding humans. Plant diseases have been known to have a disruptiveeffect on the cultivation of fruit trees, tobacco and various vegetablesas well as the utilization of plant leaves and grasses by grazinganimals.

The prevention and control of diseases is thus of prime importance toman, other mammals and poultry; considerable research has been devotedto anti-disease measures. Prior research efforts have described watersoluble extracts from marine red algae selected from the groupconsisting of Turnerella mertensiana, Schizymenia epiphytic, Turnerellapennyi and mixtures thereof as effective to inhibit the growth of herpessimplex virus, Type 1 and Type 2 and herpes zoster and to relieve thepain caused by infection attributable to such viruses.

Applications of materials containing high concentration of hormonesreduced plant stress and enhance plant tolerance to drought andsalinity. Seaweed, an excellent source of cytokinins and auxins has beenassociated with enhanced root development of grasses grown under stressenvironments. Concentration of antioxidants increase significantly inresponse to exogenous seaweed treatments. Increase of these antioxidantshad been correlated with photosynthetic capacity of plants subject toenvironmental stress.

So far as animals are concerned, seaweed supplements have been describedas providing increased nutritional value.

When animals, mammals and poultry are grown for food production, thereis generally a loss of a small but constant percentage of the animalsprior to bringing the animals to the market which may be due to lack ofnutrients, sickness, improper growing temperature and the like. Thismeans that the feed eaten prior to death of the animals and other costsexpended on the animals, which do not survive, are wasted. In addition,animals consuming costly feed for fattening which have lowered immunesystems also waste the cost of the feed and decreases the weight gainsof poultry and mammals and thus their economic value.

SUMMARY OF THE INVENTION

It has now been found that seaweed supplement, both meal andwater-soluble extract forms of seaweed, enhance immune responses inmammals and poultry when introduced into the host diet either directly,or indirectly through plants including forages.

The invention is directed to use of seaweed supplement, for example,from Ascophylum nodosum, to improve immune response in mammals andpoultry. When the seaweed supplement is included as a pasture treatmentor feed ingredient for ruminant and non-ruminant animals, poultry, andother mammals, the immune function is enhanced and health of the host isimproved. Studies show sheep that grazed treated forage had increasedblood levels of vitamin A and selenium indicating that the anti-oxidantactivity had been increased in the host as well as plants that themammals grazed. In addition, influence of the seaweed supplement onsteers that grazed forage infected with the fungus, known to result inseveral animal disorders, provided further evidence that the steers thatgrazed the treated forage responded with increased anti-oxidant activityand that the steers had improvement in their immune function. Steersthat grazed the fungus infected forage had depressed immune functionthat treatment with seaweed extract was able to reverse and to restoreto normal levels. Further the improved immune function achieved by thecattle grazing on the aforementioned pasture was retained throughfeedlot finishing even without continuation of the seaweed supplementbeing furnished to the diet. The invention was also productive inproviding grazing lambs improved antioxidant function, daily gains andtotal gains as compared to control lambs grazing non-treated pastures.

An independently inventive embodiment is directed to impartingresistance to PRRS disease in pigs that have been exposed to PRRSdisease and comprises administering a PRRS disease resistance impartingeffective amount of seaweed supplement to the pigs. Weaned pigs stressedby exposure to PRRS disease present within the swineherd were feddifferent amounts of seaweed extract or seaweed meal. The seaweedextract and meal were effective in improving the health of the pigsresulting in increased feed intake, growth rates (higher daily and totalgains) and improved feed conversion (feed:gain ratio). No pigs fed theextract or meal died while three deaths occurred within the controlgroup.

Another independently inventive embodiment is directed to mitigating thestress in lactating mares during and after weaning when the lactatingmares are physically separated from their foals and comprises prior toweaning administering to the lactating mares a weaning stress mitigatingeffective amount of seaweed supplement. Lactating mares fed seaweedsupplement prior to weaning had a substantially constant neutrophil tolymphocyte ratio for 40 days and longer after weaning whereas lactatingmares in the control group (not fed seaweed supplement) had neutrophilto lymphocyte ratios that were more than double at 28 days afterweaning.

Improvement in immune function for mammals and poultry has largeimplications in the field of mammal and poultry health. Improvement inimmune function in swine may well indicate applications to human healthand immune function as well. Improved carcass characteristics were shownby cattle, which grazed on forage treated with seaweed extract. Themonetary benefits to the industry will be significantly impacted in thepositive from producing foraging animals wherein the forage has beentreated by seaweed extract. Furthermore, the seaweed treatment offescue, for example, infected with the fungus can at least offset thenegative effects on immune function and will improve animal performanceduring the final finishing periods, i.e., feedlots. Since fescue is amajor pasture grass in much of the livestock producing areas of theeastern United States, the implications are far reaching.

The term administering seaweed supplement is used herein to encompassboth direct feeding of seaweed supplement in the diet and also feedingas a result of grazing on seaweed supplement treated pastures includingseaweed extract treated pastures and seaweed meal treated pastures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graphic presentation of the effect of seaweed on lamb wholeblood selenium showing results of Example I.

FIG. 2 is a graphic presentation of the effect of seaweed on lamb serumvitamin A, showing results of Example I.

FIG. 3a is a graphic presentation of the effect of seaweed extract andendophyte infection on immune cell response (phagocytic activity) ofsteers grazing tall fescue in 1995, showing results of Example II.

FIG. 3b is a graphic presentation of the effect of seaweed extract andendophytic infection on immune cell response (phagocytic activity) ofsteers grazing tall fescue in 1996 and 1997, showing results of ExampleII.

FIG. 3c is a graphic presentation of the effect of seaweed extract onimmune function as measured by monocyte major histocompatibility complexClass II expression (MHC Class II Activity) of steers grazing tallfescue in 1995, showing results of Example II.

FIG. 3d is a graphic presentation of the effect of seaweed extract onimmune function as measured by monocyte major histocompatibility complexClass II expression (MHC Class II Activity) of steers grazing tallfescue in 1996 and 1997 and shows results of Example II.

FIG. 4a is a graphic presentation of the effect of seaweed extracttreatment of grass on phagocytic activity during the feedlot period ofsteers that had grazed the treated grass prior to the feedlot period andshows results of Example II.

FIG. 4b is a graphic presentation of the effect of seaweed extracttreatment of grass on monocyte major histocompatibility complex Class IIexpression during the feedlot period of steers that had grazed treatedgrass prior to the feedlot period and shows results of Example II.

FIG. 5 is a graphic presentation of USDA Grades after feedlot phaseresulting from seaweed extract treated grass grazed by steers and showsresults of Example II.

FIG. 6 is a graphic presentation of marbling score after feedlot phaseresulting from seaweed extract treated grass grazed by steers and showsresults of Example II.

FIG. 7 is a graphic presentation of steers on seaweed meal-dry matterdiet having increased immune function in regard to reaction tointradermal injections of phyto hemoaglutin, and shows results ofExample III.

FIG. 8a is a graphic presentation of total gains of steers exposed toseaweed supplement during a 10 day feeding trial with seaweed extract (1and 2%) and control, followed by feedlot finishing, and shows results ofExample IV.

FIG. 8b is a graphic presentation of marbling in meat from slaughter ofsteers exposed to seaweed supplement during a 10 day feeding trial withseaweed extract (1 and 2%) and control followed by feedlot finishing,and shows results of Example IV.

FIG. 8c is a graphic presentation of USDA Quality Grades for meat fromslaughter of steers exposed to seaweed supplement during a 10 dayfeeding trial with seaweed extract (1 and 2%) and control, followed byfeedlot finishing, and shows results of Example IV.

FIG. 9 is a graphic presentation of baby pig trial total gain forcontrol, 3% seaweed meal, 1% seaweed extract, and 0.5% seaweed extract,showing results of Example V.

FIG. 10 is a graphic presentation of baby pig trial feed to gain forcontrol, 3% seaweed meal, 1% seaweed extract, and 0.5% seaweed extract,showing results of Example V.

FIG. 11 is a graphic presentation of baby pig trial total intake per pigfor control, 3% seaweed meal, 1% seaweed extract, and 0.5% seaweedextract, showing results of Example V.

FIG. 12 is a graphic presentation of baby pig trial daily gains forcontrol, 3% seaweed meal, 1% seaweed extract, and 0.5% seaweed extract,showing results of Example V.

FIG. 13 is a graphic presentation of baby pig trial gains by week forcontrol, 3% seaweed meal, 1% seaweed extract, and 0.5% seaweed extract,showing results of Example V.

FIG. 14 is a graphic presentation of baby pig trial body weights throughday 35 for control, 3% seaweed meal, 1% seaweed extract, and 0.5%seaweed extract, showing results of Example V.

FIG. 15 is a graphic presentation of baby pig trial feed intake per pigper period for control, 3% seaweed meal, 1% seaweed extract and 0.5%seaweed extract, showing results of Example V.

FIG. 16 is a graphic presentation of neutrophil to lymphocyte ratio forlactating mares for 56 days after weaning for control diet and seaweedextract at 2% of total diet and shows results of Example VI.

DETAILED DESCRIPTION

We turn firstly to the broadest form of the invention; i.e., a method ofenhancing immune response in mammals comprising administering seaweedsupplement to the mammal in amounts ranging from about 0.01% to about3.0% or even to about 5% by weight of the diet or greater for a periodof about 3 to about seven days, e.g., for 14 days, or longer.

The seaweed supplement is, for example, seaweed extract or seaweed meal.

The seaweed from which the seaweed supplement is obtained can be fromany of the various seaweed plant classifications, preferably those thathave been utilized in agriculture and include seaweeds from the plantorders Laminariaceae, Fucaceae and Gigartinaceae. Genus groups includeAscophyllum, Laminaria, Durvillea, Macrocystis, Chondrus and Ecklonia.The seaweed for the preferred seaweed supplement herein is from thegenus Ascophyllim which belongs to the order Fucaceae and is Ascophyllumnodosum. Ascophyllium nodosum is a brown seaweed which grows along theNorth Atlantic shorelines of Canada, the United States, and Europe.

We turn now to seaweed supplement which is seaweed extract.

Seaweed extract is water soluble and can be obtained by alkalinehydrolysis extraction. A preferred seaweed extract is obtained byalkaline hydrolysis extraction from Ascophyllum nodosum; commercialproducts of this kind are available from Acadian Seaplants Limited ofNova Scotia Canada, and are sold under the tradenames Acadian SolubleSeaweed Extract Powder (powder form), Acadian Liquid Seaweed Concentrate(liquid form), Tasco™-Ex (powder form) and Tasco™-Forage (powder form).Acadian Soluble Seaweed Extract Powder, Tasco™-Ex and Tasco™-Forage havethe same composition. Acadian Soluble Seaweed Extract Powder is made upof brownish-black crystals, has a seaweed-like odor, is 100% soluble inwater and has a pH of 10-10.5 in water and typical analysis shows byweight 6.5% maximum moisture, 45-55% organic matter, 45-55% ash(minerals), 1.0-2.0% total nitrogen (N), 2.0-4.0% available phosphoricacid (P₂O₅), 18.0-22.0% soluble potash (K₂O), 1.0-2.0% sulfur (S),0.2-0.5% magnesium 0.1-0.2% calcium, 3.0-5.0% sodium, 75-150 ppm boron,75-250 ppm iron, 8-12 ppm manganese, 1-10 ppm copper, 25-75 ppm zinc;alginic acid, mannitol, and laminarin carbohydrates; cytokinin, auxinand gibberellin growth promoters; and the following average grams ofamino acid per 100 grams of protein: alanine, 3.81; arginine, 0.22;aspartic acid, 5.44; cystine, trace; glutamic acid, 7.69; glycine, 3.16;histidine, 0.42; isoleucine, 1.94; leucine, 4.84; lysine, 1.33;methonine, 1.39; phenylalanine, 2.82; proline, 4.42; serine, 0.14;threonine, 1.27; tyrosine, 1.80, and valine, 3.46.

Seaweed extract is preferably applied to pasture forage as a watersolution at the beginning of the grazing season and in the middle of thegrazing season. The seaweed extract can be applied, for example, in anamount ranging from 0.3 kg/ha to 5 kg/ha, e.g., 1 to 4 kg/ha, and anapplication amount of 3.4 kg/ha (3 lbs/acre) has been used with goodadvantage. The seaweed extract (powder form) is readily dissolved in 20to 40 gallons of water per acre. Application is preferably carried outby spraying the water solution on the pasture forage using a commercialfield-type of sprayer.

Seaweed extract is preferably admixed into diet for direct feeding byinclusion at the time of feeding by top dressing or mixing into the feedat the time of feeding or by premixing at the time the diet ingredientsare combined and is included in an amount of, e.g., 0.01 to 3% by weight(powder or liquid concentrate commercial products) of the diet.

We turn now to seaweed supplement which is seaweed meal or flour.

The seaweed meal or flour can be obtained by dehydrating the seaweed,for example, by solar drying followed by low heat finish drying andprocessing the dehydrated material into a granular meal or four. Apreferred seaweed meal is obtained from Ascophyllum nodosum and isavailable from Acadian Seaplants Limited of Nova Scotia, Canada, and issold under the tradenames Acadian Kelp Meal and Tasco™-14. Acadian KelpMeal and Tasco™-14 have the same composition. A typical analysis ofAcadian Kelp Meal shows the following approximate weight percentages:moisture 12.0%, crude protein 6.0%, crude fiber 6.0%, ash (minerals)22.0%, fat 20%, and carbohydrates 52%. Analysis of Acadian Kelp Meal forcarbohydrates gives by weight 18.0-27.0% alginic acid, 3.8-8.0%mannitol, 2.0-5.0% laminarin, and 20.0-22.0other sugars. Analysis ofAcadian Kelp Meal for minerals gives 50-150 ppm aluminum, 5-15 ppmbarium, <1 ppm beryllium, 80-100 ppm boron, <1 ppm cadmium, 1.0-3.0%calcium, 1.0-3.0% chloride, 1-2 ppm chromium, <1 ppm cobalt, 1-10 ppmcopper, <1,000 ppm iodine, 100-500 ppm iron, <1 ppm lead, 0.5-1.0%magnesium, 10-50 ppm manganese, <1 ppm mercury, <2 ppm molybdenum, <1ppm nickel, 0.5-2.0% nitrogen, 0.1-0.2% phosphorus, 1.5-2.5% potassium,3-4 ppm selenium, 2.4-4.0% sodium, 100-600 ppm strontium, 2.0-3.0% <10ppm tin, 1-10 ppm titanium, 2-6 ppm vanadium and 10-50 ppm zinc.Analysis of Acadian Kelp Meal for vitamins gives 0.1-0.4 ppm biotin,30-60 ppm carotene, 0.1-0.5 ppm folic acid, 0.1-0.5 ppm folinic acid,10-30 ppm niacin, 5-10 ppm riboflavin, 1-5 ppm thiamin, 150-300 ppmtocopherols, 100-2,000 ppm vitamin C, <0.004 ppm vitamin B₁₂, and <10ppm vitamin K. Analysis of the amino acid content for Acadian Kelp Mealgave the following expressed as grams of amino acid per 100 g of proteinnitrogen: alanine 5.3, arginine 8.0, aspartic acid 6.9, cystine (trace),glycine 5.0, glutamic acid 10.0, histidine 1.3, isoleucine 2.8, leucine4.6, lysine 4.9, methionine 0.7, phenylalanine 2.3, proline 2.6, serine3.0, threonine 2.8, tryptophan (trace), tyrosine 0.9, and valine 3.7.

Seaweed meal is preferably applied to a pasture to provide seaweedtreated forage by application in dry form and solubles from seaweed mealdissolve after application so that the solubilized material is availablefor foliar uptake and/or leaches into the ground and is taken up by theforage. The seaweed meal can be applied, for example, in an amount of0.3 to 10 kg per acre.

Seaweed meal is preferably admixed into diet for direct feeding byinclusion at the time the diet ingredients are mixed or by directedaddition at the time of feeding, in an amount of, e.g., 0.01 to 5%, byweight of the diet.

In one embodiment herein, mammals, e.g., cattle or lambs, are grazed onseaweed supplement treated endophyte-infected forage, e.g.,endophyte-infected tall fescue, whereby immune function is preserved ordepressed immune function is reversed by the seaweed supplementtreatment.

Livestock grazing tall fescue infected with an endophyte, e.g.,Neotiphodium coenophialum, exhibit several disorders collectivelyreferred to as “Fescue Toxicity.” The endophyte may influence mineralcomposition of the plant and mineral metabolism in the animal. Cattlegrazing endophyte infected tall fescue exhibited signs of Cu deficiency.Selenium and vitamin E have been investigated in relation to fescuetoxicity although results have been inconsistent. It was found thatlambs grazing endophyte infected tall fescue treated with seaweedextract show increased whole blood Se and serum vitamin A. Thus, therelationships of endophyte and seaweed extract on performance andmineral status of steers were investigated.

Tall fescue is one of the most important forages grown and it is usedwidely because it is highly productive and resistant to a number ofstresses. Most tall fescue is infected with a fungus, which lives insidethe plant. The plant provides a home to the fungus, and the fungus helpsthe plant to tolerate stresses such as drought and insects. However,animals which graze infected fescue often have lowered immune systemresponse, low weight gain, reduced milk production, lowered conceptionrates and other health problems. The possibility was reviewed that thequality of tall fescue could be improved and its toxicity reduced by useof plant growth regulators. Seaweed extract is known to contain plantgrowth regulating compounds, and it was applied to tall fescue.

The seaweed supplement and amounts thereof for the embodiment wheremammals are grazed on seaweed supplement treated endophyte infectedforage, are the same as described above in relation to the broadest formof the invention with the seaweed supplement being applied to thepasture forage as described above to provide the seaweed supplementtreated endophyte infected forage.

In an independently inventive embodiment, pigs that are exposed to PRRSdisease are administered a PRRS disease resistance imparting effectiveamount of seaweed supplement. As indicated above, the seaweed supplementhas been found to improve the health of the pigs resulting in increasedfeed intake, growth rates and improved feed conversion compared to wherethe pigs are not fed seaweed supplement.

The swine industry in the United States has moved largely to confinementoperations with large concentrations of hogs produced by relatively fewoperators. Swine health, while always important, takes on greaterurgency when large numbers of hogs are housed in close proximity as isusually the case now. Porcine Reproductive and Respiratory Syndrome(PRRS) was an unrecognized viral disease of swine until described in theUnited States in 1987. Within herds, the disease spreads rapidly with upto 95% of pigs affected within two to three months. The primary mode oftransmission is by relatively close contact among pigs but the virus canalso be spread aerially and through semen from infected boars. Thedisease is characterized by abortion, premature farrowing, stillborn andmummified pigs, and respiratory disease with chronic poor performance ofnursing and weaning pigs but affects pigs of any age. Of major economicimportance, PRRS disease is thought to affect more than two-thirds ofthe herds in the United States.

For imparting resistance to PRRS disease, the seaweed supplement ispreferably fed directly to the pigs in admixture with diet. Both seaweedextract and seaweed meal forms of seaweed supplement are useful in thisembodiment. Admixture into diet is readily carried out as describedabove for the broadest embodiment herein. As indicated above, theseaweed supplement is fed in a PRRS disease resistance impartingeffective amount. When seaweed extract is the seaweed supplement, it isfed, for example, in an amount, for example, of 0.01 to 3% by weight(powder or liquid concentrate forms of seaweed extract) of the diet.When seaweed meal is the seaweed supplement, it is fed, for example, inan amount of, e.g., 0.1 to 5%, by weight of the diet. The seaweedsdescribed above in conjunction with the broadest form of the inventionare useful to provide seaweed supplement for this embodiment andpreferably the seaweed supplement is from Ascophyllum nodosum. Theseaweed supplement is continued in the diet, preferably, for the periodwhere PRRS disease resistence is important.

A special case herein is directed to baby pigs (castrated males andfemales) that have been exposed to PRRS disease and are placed in thenursery on weaning. These pigs are placed in the nursery normally at age21-35 days and are ordinarily maintained there for a five week nurseryphase. Including seaweed supplement in diets over the entire nurseryperiod for baby pigs that had been exposed to PRRS disease has beenfound to provide healthier pigs with higher daily, weekly and totalweight gains, higher body weights and improved feed conversion (lowerfeed to gain ratios) compared to control pigs, that is, where the pigsare not fed seaweed supplement. Whereas the rate of weight gain steadilyincreases for the treated pigs, the rate of weight gain decreases afterweek 3 of the nursery phase for control pigs. Thus, the feeding ofseaweed supplement has been indicated to improve the ability ofdisease-stressed baby pigs to overcome the disease challenge and improvein performance.

We turn now to the embodiment where the stress of weaning is mitigatedin lactating mares during and after weaning when the lactating mares arephysically separated from their foals by treatment comprising prior toweaning administering to the lactating mares a weaning stress mitigatingeffective amount of seaweed supplement.

Recently there has been a particular interest in how stress-relatedphysiological changes impinge upon immune function. The end of lactation(milk production) has components of both a physiological andpsychological stress. At weaning the young foal is removed from itsmother which is still responding physiologically by producing milk. Themother may still be able to see and hear her foal, which, along with thephysical separation creates anxiety in both the mother and foal. Suchanxiety stresses the mares and affects the immune response of the maresby decreasing the number of lymphocytes resulting in increasedneutrophil to lymphocyte ratio. This effect is caused by stresshormones. The principal stress hormone, cortisol, has been shown tocause a shift in the number of various white blood cells causingincrease in neutrophil to lymphocyte ratio and decreasing immuneresponse. This embodiment stabilizes the neutrophil to lymphocyte ratioand prevents significant increase thereof in mares after weaning therebymitigating the stress of weaning.

For mitigating the stress of weaning in lactating mares, feeding of theseaweed supplement is preferably started at least five days prior toweaning, very preferably at least 10 days prior to weaning or 10 to 30days prior to weaning, e.g., starting 14 days prior to weaning, and ispreferably continued until weaning occurs or even after weaning occurs,e.g., up to seven days after weaning occurs.

The seaweed supplement is directly fed to the mares in admixture withthe diet or is applied to pasture forage consumed by the mares, asdescribed above for the broadest embodiment herein. As indicated above,the seaweed supplement is administered in a weaning stress mitigatingeffective amount as indicated by stabilization of neutrophil tolymphocyte ratio to an increase of less than 40% or even a decrease,e.g., of up to 20 or 30%. For direct feeding, admixture with the diet isreadily carried out as described above and when the seaweed supplementis seaweed extract, it is fed, for example, in an amount, for example,of 0.01% to 3% by weight (powder or liquid concentrate forms of seaweedextract) of the diet and when the seaweed supplement is seaweed meal, itis fed, for example, in an amount of, for example, 0.01 to 5% by weightof the diet. The seaweeds described above in conjunction with thebroadest form of the invention are useful to provide the seaweedsupplement for this weaning stress mitigating embodiment, and preferablythe seaweed supplement is from Ascophyllum nodosum.

The invention is illustrated by the following examples.

EXAMPLE I

Thirty-two wether lambs (Dorset x Rambouillet x Finn) grazedendophyte-infected (70%) tall fescue during two experimental periods (26and 21 days). Lambs were blocked by weight, randomized within blocks,and assigned to one of three seaweed treatments in a complete randomizedblock design with four replications/treatment. Seaweed extract(Tasco™-Forage) treatments, applied foliarly on April 5 and June 20,were 0, 1.5, and 3.0 lb acre. Paddocks were 0.09 acre in size. Lambs hadaccess to water and NaCl blocks at all times. Lambs were grazed duringtwo periods: May 21-June 17 (26 days) and July 21-August 10 (21 days).Lambs were weighed and blood was collected by jugular puncture at thebeginning and end of each trial period. Lambs were weighed andre-randomized to treatments four days prior to Period 2.

Samples to determine forage mass and nutritive value were taken prior toinitiation of each period and 31 days after the end of Period 2. Foragemass samples also were taken at the end of each period. All paddockswere mowed at the end of the Period 1 to equilibrate forage mass perpaddock. Samples were analyzed for concentrations of neutral detergentfiber (NDF), acid detergent fiber (ADF), hemicellulose, cellulose,lignin, crude protein, and total nonstructural carbohydrate. In vitrodry matter digestibility also was determined on the samples. Forage wasalso analyzed for pyrolizidine (University of Kentucky, Lexington, Ky.)and ergot (Auburn Fescue Diagnostic Laboratory, Auburn, Ala.) alkaloids.For Period 2, serum was analyzed for vitamins A and E, and whole bloodwas analyzed for Se (VA-MD College of Veterinary Medicine). Plant andserum minerals were determined by inductively coupled plasmaspectrometry.

During Period 1, lambs grazing forage treated at the high seaweedextract rate maintained weight while control lambs lost weight (Table1). Lambs grazing treated forage had greater daily gains in Period 2than did wethers on control pastures. No effect of treatment was seen onserum vitamin E concentrations, but serum vitamin A increased linearly(FIG. 2). Selenium in whole blood (measured after Period 2 only) wasincreased linearly by seaweed extract treatment (FIG. 1). An increase inselenium likely indicated an increase in glutathione peroxidase in theanimal.

TABLE 1 Influence of seaweed extract (SWE) on average daily gain, serumvitamin A, and whole blood Se of wether lambs grazing endophyte-infectedtall fescue. SWE, lb/acre Item 0 1.5 3.0 S.E. Period 1 Average dailygain, lb/d −.07 −.11 0 .07 Period 2 Average daily gain, lb/d^(a) .07 .26.24 .07 Serum vitamin, ppb^(b) 306 331 371 25 Whole blood Se, ppb^(c)241 264 274 13 ^(a)Indicates difference between control vs. the mean ofSWE treatments (P ≦ .05). ^(b)Linear effect of SWE (P ≦ .13). ^(c)Lineareffect of SWE (P ≦ .10).

Seaweed treatment of infected tall fescue increased antioxidant activityin the animal, a first step toward the potential to alter immunefunction and animal health.

Lambs grazing seaweed extract treated forage had greater weight gainsand also had increased concentrations of vitamin A and selenium in theirblood.

The results show that seaweed extract treatment of tall fescue improvesproduction of animals grazing the tall fescue and that seaweed extractis helpful in reducing tall fescue toxicity.

EXAMPLE II

Forty-eight yearling Angus and Angus X Hereford steers were randomizedto four paddocks of E+ (80%) and four paddocks of E− (<5%) Ky-31 ′ tallfescue at Glade Spring, Va. in 1995, 1996 and 1997 for a total of 144steers. Forty-eight yearling ¾ Angus X ¼ Brahman steers were randomizedto four paddocks of E+ (100%) and four paddocks of E− (<5%) Ky-−′ tallfescue at Prairie, Miss. in 1996 and 1997 for a total of 96 steers. Ateach location, two paddocks of E+ and two paddocks of E− tall fescuewere sprayed with seaweed extract (A. nodosum; Tasco#-Forage, AcadianSeaplants Limited, Dartmouth, Nova Scotia, Canada) at 3 lb/acre beforesteers began grazing in April and again in mid-summer. At bothlocations, steers grazed continuously from April until October. Steerswere weighed and rectal temperatures were recorded initially, every 28days, and at the end of the grazing season. All cattle received standardhealth care including immunization for Pasteurella hemoletica,Infectious Bovine rhinotrachetis, Bovine Virus Diarrhea, Clostridiaperfringes C&D and were treated with Ivomec for internal parasites.Blood samples were taken by jugular vena puncture initially, and in May,July, and September for analysis of serum minerals and vitamin A.Pastures were sampled each time cattle were weighed for forage mass byclipping two 20-fl strips/paddock, and samples for mineral analysis weretaken by diagonally walking each paddock and sampling fescue every 20ft.

Concentrations of minerals were determined in fescue and in blood serumby measuring atomic emission with an inductively coupled plasmaspectrometer after digestion with nitric and perchloric acids. Greenleaves of tall fescue were collected from within each pasture inVirginia at 28 day intervals beginning in April and ending in Novemberfor determination of (superoxide dismutase) SOD activity. InMississippi, green leaves were collected from each pasture in July,September and October in 1996 and at 28-day intervals in 1997. Thesesamples were frozen in liquid N in the field and were stored in afreezer at 100 degrees Fahrenheit until SOD activity was measured.Samples collected in Mississippi were transported to Virginia in liquidN and were analyzed as described previously. Phagocytic activity andmonocyte major histocompatibility complex Class II expression (MHC ClassII) of the monocyte cell population was measured using a cell-boundfluorochrome detected through flow cytometry. Data were analyzed usingan ANOVA.

Immune response was influenced by treatments. Total leukocyte countswere increased in Virginia steers grazed on seaweed extract treatedendophyte infected fescue compared to non-treated endophyte-infectedfescue, and this was particularly evident in July and August. However,the endophyte free group of steers demonstrated the highest leukocytecounts of all treatment groups. Cell function appeared to be influencedby seaweed extract treatment. In general, application of seaweed extractto endophyte infected fescue enhanced immune response in grazing steersand in both endophyte infected and endophyte-free groups duringcross-country transport to the feedlot. Antioxidant activity in responseto seaweed extract, particularly SOD, a Cu-dependent enzyme, may haveinfluenced the immunocompetence of these steers directly by increasingsteer SOD concentrations or indirectly as a source of bioavailablecopper in the diet to enhance monocyte function.

Increased immune function in cattle that grazed seaweed treated pastures(both infected and non-infected fescue) remained with cattle duringtransportation to the feedlot and throughout the 132 day finishingperiod. Carcass evaluation showed that cattle that had grazed theseaweed treated pastures had USDA carcass grades that were about ½ agrade higher than cattle not exposed to seaweed. Furthermore, anincrease in marbling of the meat was indicated.

Results are shown in FIGS. 3a, 3 b, 3 c, 3 d, 4 a, 4 b, 5 and 6.

In FIG. 3a, “a” indicates an endophyte effect (P<0.05), “b” indicates anendophyte by Tasco™ interaction (P<0.01), “c” indicates a Tasco™ effect(P<0.08), “d” indicates an endophyte by Tasco™ interaction (P<0.05) and“e” indicates an endophyte effect (P<0.06), and n=2 for each mean wherepasture is the experimental unit.

In FIG. 3b, “a” indicates a Tasco# by endophyte interaction (P<0.05),“b” indicates a Tasco# by endophyte interaction (P<0.01) and “c”indicates a location by Tasco™ by endophyte interaction (P<0.05), andn=12 for each mean where pasture is the experimental unit.

In FIG. 3c, “a” indicates an endophyte effect (P<0.05), “b” indicates anendophyte by Tasco™ interaction (P<0.01), “c” indicates an endophyte byTasco# interaction (P<0.05) and “d” indicates a Tasco™ effect (P<0.08),and n=2 for each mean where pasture is the experimental unit.

In FIG. 3d, “a” indicates a Tasco™ by endophyte interaction (P<0.05),“b” indicates a Tasco™ by copper interaction (P<0.05) and “c” indicatesa location by endophyte interaction (P<0.05), and n=12 for each meanwhere pasture is the experimental unit.

In FIG. 4a, “a” indicates a Tasco™ by endophyte interaction (P<0.05),“b” indicates a location by Tasco# by endophyte interaction (P<0.05) and“c” indicates a Tasco™ by endophyte interaction (P<0.10), “e” indicatesa Tasco™ effect (<0.05) and “f” indicates an endophyte effect (P<0.01),and n=2 for each bar where pen is the experimental unit.

In FIG. 4b, “a” indicates Tasco™ by endophyte interaction (P<0.05), “b”indicates a Tasco™ effect (P<0.08), “c” indicates a Tasco™ by endophyteinteraction (P<0.07), “d” indicates a Tasco™ by copper interaction(P<0.07), “e” indicates a Tasco™ by copper interaction (P<0.05), “f”indicates a Tasco™ effect (P<0.02) and “g” indicates an endophyte effect(P<0.05), and n=12 for each bar where pen is the experimental unit.

In FIG. 5, “a” indicates a Tasco™ effect (P<0.15) and n=12 for each barwhere pen is the experimental unit.

In FIG. 6, “a” indicates a Tasco™ effect (P<0.05) and n=12 for each barwhere pen is the experimental unit.

These trials showed that a positive immune response resulted fromtreatment of forage with seaweed and that it was not restricted to theendophyte infected fescue. These trials showed that the response waslong term (132 days) after treatment ended and that there was animprovement in carcass value related to seaweed treatment.

EXAMPLE III

Two groups of steers (48 cattle in each group) were fed 0. 1.5, 3% byweight of their total daily dry matter intake as seaweed meal (AcadianKelp Meal). Group one steers were fed a diet based on sorghum whilegroup two was fed a diet based on corn. The trial was continued for 129days at which time all steers were slaughtered.

Inclusion of seaweed meal reduced daily dry matter intake andperformance of steers. However, as shown in FIG. 7, there was increasedimmune function particularly in regard to reaction to intradermalinjections of phyto hemoaglutin.

Inclusion of seaweed meal directly in the diet of beef cattle resultedin enhanced immune response in some indicators but was less effectivethan treating pastures with seaweed extract and allowing cattle to grazethe treated forage.

EXAMPLE IV

Twenty-four steers were fed a diet of 0, 1, and 2% seaweed extract(Acadian Soluble Seaweed Extract Powder) for 10 days in a feeding trial.At the end of the 10-day period, the extract was removed from the dietand all steers were fed the control diet. Daily gains were recorded. Theresults indicated a trend for a linear increase in total and daily gainin response to seaweed level (FIG. 8a). The improvement in performanceappears to be consistent with research with pigs and lambs. Atslaughter, there was a linear increase in marbling and in response toUSDA Quality Grade in response to feeding seaweed extract. (FIGS. 8b and8 c). The improvement in marbling and grade appears to be consistentwith results of research where seaweed extract was sprayed on tallfescue pastures grazed by steers.

EXAMPLE V

One hundred and twenty-eight baby pigs (males and females) were blockedby weight and breed and were randomized within blocks to four treatmentsas following: Control, 3% seaweed meal (Tasco-14™), 0.5% seaweed extract(Tasco-EX™), and 1% seaweed extract (Tasco-EX™) as a percentage byweight of the diet. Percentages were calculated as a percent of the dieton an as-fed basis. There were four pens (replications) per treatmentwith eight pigs per pen. Pigs were started on the experimental diets atweaning and were fed the diets during the entire 35-day nursery phase.Weights of pigs and feed intake were determined weekly. All pigs hadbeen exposed to Porcine Respiratory and Reproductive Syndrome.

The diet aside from seaweed supplement was as follows: 64.2% groundmilo, 32.5% soybean meal, 1.4% dicalcium phosphate, 1.1% calciumcarbonate, 0.5% vitamin premix, 0.2% trace mineral premix and 0.1%magnesium oxide, the percentages being by weight. The seaweed supplementmeal and the seaweed supplement extract (powder form) were admixed withdiet by mixing in a mixer together with the other diet constituents.

Results are shown in FIGS. 9-15 where “Ext.” means seaweed extract. Asshown in FIG. 12, the diets with seaweed supplement gave higher dailygains. As shown in FIG. 13, the diets with seaweed supplement gavehigher weekly gains starting in week 3 of the nursery phase. As shown inFIG. 9, the diets with seaweed supplement gave higher total gain. Asshown in FIG. 14, the diets with seaweed supplement gave higher bodyweights starting at day 30 of the nursery phase. As shown in FIG. 11,the diets with seaweed supplement gave higher total intake per pig; FIG.15 shows the intake per pig in the period of weeks 1 and 2, in theperiod of week 3, in the period of week 4 and in the period of week 5.As shown in FIG. 10, the diets with seaweed supplement gave lower feedto gain ratios.

Performance of control pigs declined over the feeding period whileperformance of treated pigs improved.

The results indicate that direct feeding of seaweed supplement improvedthe ability of disease-stressed baby pigs (by exposure to PRRS disease)to overcome the disease challenge and improve in performance.

EXAMPLE VII

In this study, 10 mares and their foals were fed seaweed extract(Tasco™-Ex) in amount of 2% of the total diet and 10 were fed a normaldiet, for 14 days prior to weaning.

The diet aside from seaweed supplement was as follows: 46% oats, 37%corn, 5.5% soybean meal, 5.4% molasses, 4% fat, 1.1% dicalciumphosphate, 0.7% calcium carbonate and 0.3% vitamin/mineral premix.

The seaweed extract powder was admixed with diet to provide diet for themares fed seaweed supplemented diet by hand mixing into the diet at thetime of feeding. Each mare was individually fed.

Blood samples were collected at the start of the study, at weaning, andthree times more to determine the effect of weaning and handling on theneutrophil to lymphocyte ratio aspect of the immune system.

The results are shown in FIG. 16.

Normally, horses have about 54% neutrophils and 35% lymphocytes which isa ratio of neutrophils to lymphocytes of about 1.5:1. As indicated inFIG. 16, control mares (not fed seaweed supplement) had elevatedneutrophil to lymphocyte ratio increasing to near 4.0 on day 28. Asshown in FIG. 16, for mares fed diet with seaweed supplement, theneutrophil to lymphocyte ratio was consistent at around 1.5.

These findings indicate that feeding seaweed supplement to lactatingmares prior to weaning mitigated the stress of weaning and handling,especially on day 28.

Similar results of mitigating the stress of weaning and handling areobtained, when the lactating mares are grazed on seaweed extract treatedpasture or seaweed meal treated pasture instead of being directly feedseaweed extract and diet as described above.

For purposes of this specification and figures, the followingabbreviations are defined as follows:

S.E. standard error;

E+ endophyte infected;

E− no endophyte infection;

T+ with seaweed; and

T− without seaweed.

The terms and expressions which have been employed are used as terms ofdescription and not of limitation, and it is not intended in the use ofsuch terms and expressions to exclude an equivalence of the featuresshown and described or portions thereof, since it is recognized thatvarious modifications are possible within the scope of the inventionclaimed.

What is claimed is:
 1. A method of enhancing immune response asmanifested by increased phagocytic activity and increased monocyte majorhistocompatibility Complex II expression in a mammal having depletedimmune function as manifested by depleted phagocytic activity anddepleted monocyte major histocompatibility Complex II expressioncompared to basal levels of phagocytic activity and monocyte majorhistocompatibility Complex II expression in the mammal comprisingadministering seaweed supplement to the mammal in a phagocytic activityincreasing effective and monocyte major histocompatibility Complex IIexpression increasing effective amount for a period of about three toabout seven days or longer.
 2. The method of claim 1 where the seaweedsupplement is seaweed extract.
 3. The method of claim 2 where theseaweed extract is obtained from the seaweed Ascophyllum nodosum.
 4. Themethod of claim 3 wherein the seaweed extract is in powder orconcentrated liquid form.
 5. The method of claim 1 where the seaweedsupplement is seaweed meal.
 6. The method of claim 5 where the seaweedmeal is obtained from Ascophyllum nodosum.
 7. The method of claim 1where the seaweed supplement is administered in an amount ranging from0.01% to about 5% by weight of the diet.
 8. The method of claim 7 wherethe mammal is one selected from the group consisting of cattle andsheep.
 9. A method of enhancing immune response as manifested byincreased phagocytic activity and increased monocyte majorhistocompatibility Complex II expression in a forage consuming mammalhaving depleted immune function as manifested by depleted phagocyticactivity and depleted monocyte major histocompatibility Complex IIexpression compared to basal levels of phagocytic activity and monocytemajor histocompatibility Complex II in the mammal comprising applyingseaweed supplement to pasture to provide seaweed supplement treatedforage and grazing the mammal on the seaweed supplement treated forage.10. The method of claim 9 where the forage is endophyte infected forage.11. The method of claim 10 where the seaweed supplement is seaweedextract from Ascophyllum nodosum and is applied to the pasture byspraying a water solution of seaweed extract on the pasture in an amountof seaweed extract ranging from 0.3 kg/ha to 5 kg/ha.
 12. The method ofclaim 10 where the seaweed supplement is seaweed meal from Ascophyllumnodosum and is applied in dry form to the pasture in an amount of 0.3 to10 kg per acre.
 13. The method of claim 9 where the mammal is oneselected from the group consisting of cattle and sheep.